In the existing art, data needs to access a great number of value added service devices, such as an anti-virus device, an acceleration device, a firewall device and a Network Address Translation (NAT) device when data accesses a network. Flow without distinguishing for differences must pass through these service devices once, so unnecessary burdens are caused on these devices, and optimization of service resources is limited, and the configuration is complex, and it is difficult to realize a rapid change of the service configuration.
For the above-mentioned problem, the existing art proposed a service chain manner SFC, namely, integrating all services for servicing, virtualizing a Service overlay layer, forming an own service topology and decoupling from an underlying network to be not limited by an underlying network structure. The architecture is as shown in FIG. 1. Services through which flows will pass are determined by SFCs. The SFC classifies packets and allocates different SFCs to different levels of flows (by an entrance classification device) through adding a Service Function Path Identifier (SFPID) for each SFC. A forwarder forwards the packets according to the identifiers of the SFCs. Thus, different service chain processings can be implemented for different flows to meet differentiation requirements.
For these Service Function (SF) entities, when processing flows are excessive, corresponding SF entities cannot process a great number of flows in time, and the reliability of a system will be reduced.